Descent into the Depths of the Earth

My 5e PCs are probably going to delve into the Underdark tomorrow, so it's high time I get all that sorted.  Luckily, it gave me the opportunity to dig into Patrick Stuart's Veins of the Earth in greater detail.  (I also finally detailed the main tunnels winding underneath the Sorrowfell Plains.)

The following forms the network of caves known as "the Trials of the Chained."  (If you're playing along at home, the entrance to this network is in Hex 90.46.  Or more accurately, under it.)  Black represents the tunnels formed by Torog's torturous descent into the depths.  Blue represents the subterranean descent of the River of Tears as it winds its way through the earth.  Red represents some old mining earthworks, probably crafted by the Deep Janeen.

Assume standard six-mile hexes.

Click to enlarge.

As for the settlements on the map, they are:

Chooldubrool: Population 950.  This mad kuo-toa temple-city reveres the manufactured deity Turladebaoth, an effigy of mud and bone built along the riverbed.  They additionally serve the aboleth known only as “The Cold Eye of Crushing Aeons.”

Chornodom: Population 155.  This village of the ghouls rests in ancient tunnels, and has secret paths to both the Ghoul Market and the Plane of Dreams.

Cinlu Tlurthei: Population 17,200.  A dark elf metropolis, mentioned a few times in my notes but never detailed until now.

The Citadel of Smokeless Fire: Population 3,100.  This Deep Janeen outpost is run by The Omnipotent Dream of the Mountain's Heart, an efreeti lord.

DA VILG (or DA VILUJ): Population 165.  This village of the Cambrimen sits lazily on the banks of the river.  Their drow “slaves” have actually turned the stupid Cambrimen into their cult.  (“HEER DAH WURD!  DAH SPIDR WURD!”)  The 58 or so Cambrimen can’t figure out that their 107 dark elf “slaves” actually run this village and use it to make note of any threats coming down river so that they can warn their masters in Cinlu Tlurthei.

Redoubt of the Deep Myconids: Population 660.  This colony of 33 myconid circles plumbs the depths of the Cosmic Overmind.

Svirfneblin Trading Post: Population 1,500.  Many travelers in the Trials of the Chained miss this hidden outpost, more properly known as Sulflanur to the Svirfneblin.

Village of the Blind Antler Men: Population 135.  Here the Blind Antler Men live in quiet contemplation, withdrawn from the greater society of filthy humanoids.

I'm also kinda-sorta adapting the out-of-print adventure Hecatomb into a usable adventure for my purposes, so I made a Veins cave network for it.  If you want a big-ass cave network, the Vaults of Gnashing Teeth are also here.  The circled cave is the one that actually contains the Acropolis and the core Vault of Gnashing Teeth from Hecatomb, but of course, do whatever you want with it:

Click to enlarge.

Also, please don't record my terrible handwriting samples for sympathetic magic.